A Simple Guide To Circulating Nucleic Acids: What Are They And Why Are They Important?

 

Welcome to another post on liquid biopsy! Today we are going to look at circulating nucleic acids. We all have heard of nucleic acids at some point in our life. Nucleic acids contain genetic instructions that make an organism grow and develop. DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are the main classes of nucleic acids. They are present in all cells of an organism. Then what are circulating nucleic acids??? Sometimes the cells release these nucleic acids into the blood or other body fluids. Since blood is more commonly studied, when we talk about “circulation“, we are mostly talking about blood, unless it is mentioned otherwise. Because these nucleic acids are present in the blood circulation, they are called circulating nucleic acids. Because these nucleic acids are present outside the cell, they are also called cell-free nucleic acids, like cell-free DNA or cell-free RNA. 

In 1948, Mandel and Mattais reported for the first time that nucleic acids are present in human plasma. Much later, Leon et al reported that the levels of circulating DNA in cancer patients was much higher than in normal people. This is when circulating DNA came into the spotlight as a simpler option to tissue biopsy. Soon, I will be posting a series of posts on circulating DNA and RNA. We will discuss the ways by which they are released from the cell. Later posts will describe the approaches by which they are analyzed.

 Good day!!

References:

1. Mandel P, Metais P. Nuclear acids in human blood plasma. Comptes rendus des seances de la Societe de biologie et de ses filiales. 1948 Feb;142(3-4):241-3.

2. Leon SA, Shapiro B, Sklaroff DM, Yaros MJ. Free DNA in the serum of cancer patients and the effect of therapy. Cancer research. 1977 Mar 1;37(3):646-50.